Ewa Wredle

Feed scarcity and land degradation are major constraints to livestock production in the drylands of Sub-Saharan Africa (SSA). This systematic review assessed the most commonly studied grass and forage legume species and how grass–legume mixtures affect forage yield and nutritive value in SSA drylands. Following PRISMA 2020 guidelines, Web of Science and Scopus were searched for peer-reviewed studies. A total of 32 studies met the inclusion criteria, covering ten countries, with most studies conducted in Kenya, Nigeria, Tanzania, and Ethiopia. The review identified 91 forage species (55 legumes, 36 grasses), with Centrosema pubescens and Chloris gayana being the most frequently studied legume and grass species, respectively. Of the 20 studies reporting dry matter yield in grass–legume mixtures, 17 (85%) showed increases of 13–500% compared with grass monocultures, while three (15%) reported decreases of 2–37%. Nine studies compared forage nutritive value, with reported crude protein of mixtures ranging from 9.6% to 14.4% of DM. The evidence base was limited by substantial heterogeneity in species combinations, management practices, the small number of contemporary studies, and limited assessment of socio-economic factors influencing adoption. Further research should prioritize long-term, participatory and farmer-managed evaluations across contrasting environmental and socio-economic contexts.

Drylands face urgent development challenges that are complex and interconnected, requiring holistic systems-based approaches. Here, we present a social–ecological systems framework to guide research, policy, and action across disciplines and sectors towards sustainability transformations in drylands for improved livelihoods and enhanced ecosystem, livestock, and human health. Our conceptual framework integrates three non-exclusive and complementary lenses of human-driven transformations: systemic, structural and enabling/grassroots change. Based on these three complementary lenses, along with three main phases of transformation and key associated actions, we briefly illustrate the framework’s value through the case of the Karamoja cross-border region of East Africa. We show how the framework can be used as an entry point to identify and analyse key challenges and their interlinkages; envision desired social–ecological systems; and explore pathways towards sustainability. The framework provides actionable guidance to co-develop context-specific interventions that support sustainability transformations in drylands.

A cross-sectional study on 156 smallholder dairy farms in Rwanda was carried out to assess the association between farm management practices and milk yield and quality. A pre-tested questionnaire was used to collect data on cow characteristics and farm management practices. Milk yield was recorded at household level, milk composition was monitored using a Lactoscan device (Milk Analyzer). Somatic cell count (SCC) was determined using a DeLaval cell counter (DCC). A Delvotest SP-NT kit was used to determine antibiotic residues in raw milk. Most dairy cows were kept in zero-grazing system (84.6%) and most farmers had less experience of dairy production (78.2%). Mean daily milk yield was 3.9 L/cow and was associated with type of breed, milking frequency, stage of lactation, and parity. Mean milk content of protein, fat, lactose and solid non-fat, and density were normal and showed no association with different management practices. Based on SCC analyses, 65.8% of the milk samples with less than 300,000 cells/mL were graded as acceptable for delivery to a milk collection centre (MCC) and 12.9% of the samples tested positive for antibiotic residues. These findings suggest low milk yields on smallholder farms in Rwanda that are attributable to type of breed and prevalent high level mastitis, among other factors. The results also indicate possible non-compliance with withdrawal periods, resulting in antibiotic residues in milk, which has public health implications for consumers. Routine testing at MCC for both SCC and antibiotic residues is important for quality control.

Heat stress in dairy cows can cause an increase in body temperature and respiration rate, and a decreased feed intake leading to reduced production. Dairy cows are better at handling heat when they have access to shade. Therefore, this study aimed to determine the effects of providing shade to high-yielding dairy cattle during the summer in the Swedish climate. Twenty high-yielding Swedish Red dairy cows, held on pasture, were divided into two groups, one with access to shade (S) and one without (NS). Milk production was recorded daily and shade temperature and relative humidity were recorded at 10 min intervals at pasture. A major effect of heat stress was found in cows in early lactation in the NS group. In this group, a high mean temperature two days before and a high THI two days before affected the milk production negatively (p < 0.001), which was the same for the maximum temperature and maximum THI measured on the same day (p < 0.001). Increases in the mean temperature and THI two days before also affected milk production negatively (p < 0.05) for cows in early lactation in the S group, though to a lesser extent. This study suggests that dairy cows in early lactation benefit from access to shade during summer.

Aim: This study aimed to examine the effects of feeding or abdominal brushing on the release of the hormones oxytocin, ACTH and cortisol during milking in dairy cows.Methods: Twelve cows in early lactation were used (2 × 2 factorial experimental design), testing the effects of two types of sensory stimulation during milking over a 3 day period; feeding concentrate or manual abdominal brushing (1 stroke/s). Blood samples for hormone analyses were collected at time at −15, −1, 0 (onset of cluster), every min for 8 min, at 10, 12, 14, 16, 30, and 60 min. Hormone levels were assayed and AUC was calculated.Results: Milking was associated with an immediate and significant rise of oxytocin. When milking was combined with feeding, significantly higher levels of oxytocin were observed at 2 and 4 mins (p < 0.05). No effect of brushing on oxytocin levels was observed. Milking alone was associated with a significant rise of ACTH levels. Feeding in connection with milking reduced the immediate rise of ACTH levels (p < 0.05) and AUC (p < 0.02), whereas no effects of brushing were found. Milking caused a progressive rise of cortisol levels. Concomitant feeding did not influence cortisol levels, whereas brushing significantly decreased cortisol levels at 1, 5 and 14 mins after onset of milking (p < 0.05).Conclusion: Feeding increases oxytocin release in response to milking and decreases ACTH levels. Abdominal brushing did not influence these variables, but decreased cortisol levels. These data demonstrate that activation of afferent vagal nerve fibres and of cutaneous sensory nerves originating from the abdominal skin in front of the udder influence milking related hormone release differently.

Small ruminants such as goats have a higher preference for browse species than cattle and sheep. In a meta-analysis of 42 papers describing 117 experimental treatments found by a search performed in June 2021 in PubMed and Web of Knowledge, we examined the general effect of including foliage in the diet of goats, replacing grasses, on dry matter intake and average daily weight gain. The inclusion requirement for a paper was that it described a controlled trial with a control diet of grass and with grass replaced by foliage in the experimental diet. Publication bias was estimated by calculating the Fail-safe n. Random effects analyses were conducted, using effect size calculated as Hedges’ d. The results showed that inclusion of foliage increased feed intake (Hedges’ d = 1.350, SE = 0.388) and average daily weight gain (Hedges’ d = 1.417, SE = 0.444) compared with a grass-based control. The positive effect of foliage inclusion on dry matter intake was associated with lower neutral detergent fiber (NDF) and higher crude protein (CP) in the foliage than in the grass it replaced. The positive effect on average daily weight gain was associated with higher CP concentration in the foliage than in grass. Foliage inclusion level showed a quadratic relationship with dry matter intake, with maximum dry matter intake achieved at a level of 50–60%. There was wide variation between the studies reviewed, and this variation was not reduced by subgroup analysis based on different kinds of foliage. In conclusion, the addition of foliage to goat diets can increase feed intake and daily weight gain, as an effect of the dietary preferences of goats and of generally higher nutritional value in foliage species compared with natural/semi-natural grass species.